Tube support for heaters



Nov. 25, 1952 o. c. scHAUBLE ET AL TUBE SUPPORT PoR HEATERS 2 SHEETS-SHEET 1 Filed Dec. 23, 1949 A TToR gy o o o oo oo cow Patented Nov. 25, 1952 TUBE `'SUIPBRT FORfHET-ERS OttoU.` SchaublgzM'unt Kisco; N' Y.; andfE'dwardiFancislTibb'etts, Cos Cob, Conn., assignorsito TheLummuSL-iCompaxm'Ne-w 'York;iN.'Ys, a corporation of Delaware!i Application December 23, 1949;' S'rial'No." 134;`646

tact bythe'gases'and'wh'en the-'lattercon'tain certaiif corrosives" derived from thee-fuel' employed' the-supports: are^ subject' tof corrosivevattack: Si'xclattaclisparticularlysevereewhenthe fuel is'oil containin'gwanadiuin and' sulfur: When the'combustion'gases the metal `fof-"the"tube supi; ports'is'vulnerable' to 'attack'th'ereby at-'tempera'- trn'es^of"'1250lF;-' an'ct'above;- In fact; the 'rn-etal then'corrodes'so rap'd'ly'that in'a"sh'0rttime the cube'supports-break= and permit-the tubesztov'sa'g'f Thusya serious problem'has'existed in' 'cases where heaters 'are dependent;'for'reasons of convenience and *economic upon"vana'dium1bearing'fuel'"oils Tlivisproblm t has ded f metallurgical v'solution nOsuitablemi'eta-l Forallcy has been found-*which will fresistcorrosion' by'van'afdi'unroxides;`

Important i objects fof "the present 'invention'are to provide a tube '-suppjortwitlfmeans"forfeft tually; shielding the' metal ofitlie; support' from contact"'with.the combustion 'products and" cor rosion agents "'therein; 'to' provide.' a" tube" support with` ai sheathing, or' 'j acket" designed to `excludev thefcomb'ustion: gases 'from'them'etal body'ofth'e support; and'to `provi'm'ersucha sheathing'formed of ""lceramio' refractory material and" designed to rendr'it'durable under'th'e high" temperatures'of th'eeh'eater.`

Otherobjects"and'adirantages'of'thenvention will lapp'ear'fr'orn the"follo`wing"description'taken in" connection' with" the accompanyingdrawin'gsi In'thedrawings; j Figsy 1"' is =a-'vertical sectional View of'ia" heater embodyingatlieiiivention;

' Fig: Zis '-afsi'dfelevation upon-a larger/scale; of

2' Figs; 4; 5 and 6y aref-enlarged` detail sections Aon the-"lines l2-4gvr 52-5 and" Iii-6L respectively,` of

Fig-E' 7"is' a View' similar to- Fig: 2? showing a modified form 'of the-'invention Fig: 8fis'an enlarged vertical section on the line Si-Soi Fig; 7'; and

Figa' 9is-a detail"section showing'anch'orages b'etween'the body` of the 'tube support andthe reinforcing networks `of the sheathing.

In Fig. 1 thejimproved' tube supports are shown as employed in' aV `heater for hydrocarbon 'uicls of tHe'type=-disclosed in-reissued'U.` S. Patent vanadium'- oxides* andsulfur compounds* occur 20 combustion'chamber-'defined by side' wallsI; opposits' en-dwalls; onef'of lwhich lis shown' ati 2,-' a hearth-3 andfa-banklof'vhorizontal roof Vtubes in'- oludi-ng 'aYloWer-'row of y'tubes #and anupperrow` of 'tubes =5f-which 'support a diiusion bale 'formed by=til`ef`- Such a-'b'afe is `-dsclosecl :in -U. S, Patent f2 147,610. A dividing' wall 'Ia/ extendsfrom the hearth S Vto a" pointshort of thesroof bank.' Each'oftheiside-Wal-ls I, bears "afverti'cal bank of horizontalftubese. The hearth has burners 8 distributed'l over its area; andthe end Walls may al-sobefprovided Iwith'fburners 9 atopposite sides of theldividing' wall 6a. A roof structure I 0 spaced-"above theV diffusion bae defines therewith ai plenum-lV chamber I I ywhich roloens at one -end thereof -'into aL convection'- heating chamber I2 defined-by `onef'of fthe'side'walls' I; anouter 'wall I 3-land abottom'* wall I I lli` One lor 'more banks of tubes"L I extends: through Athe convection' cham'- ber and the-'latter has 'an outlet I6 for'com'bustion gases located below the tubes and communicating with* astack; not shown'.` The present invention is fsh'own" as embodied Vin 'hanger' members S 'em pioyed to Isupport'the tubes '4 and 5:1 However,y the' invention' mayv b'eemb'odied in members "S which support the* tubes" 1'r uponl the side' walls or'inany-tube supports whichare'disp'osed for contact 'with hot combustion gases.

ReferringtoFigs: 1'to 6 inclusive,` the' struc= turewo'each'tubey supports includes" a'body` I1 preferably formed zof a high' heat resistant metal alloy; such as 25"- I 2 "chrom'ehnickel, for example.' In' the 'present linstance I the body' is 'in' 'the' form 'of afilfatpl ate 'in' a vertical plane.' The plate 'has re'- cesses'for receivlnglthetub'es 4 and '5J Thereisa' horiaontalrowbfrecesses'in the form of holes'I 8 to receive the lower tubesdfand a'horiz'ontal row of'f recesses in the '-iorn'rA of vnotches` I 9 to receive thefup'pertub'es 5Ly The holes l8 are substantially largefthanY the tubestherein; and the notches'l arefwider thanf'theldiameterof the tubes'S- The body is also formed with upwardly extending tongues 20 which are bolted, as at 2|, to suspension members 22, and the latter are anchored at their upper ends in any suitable manner to the roof structure lll.

Each tube support S has its body encased in a sheathing 23 of ceramic refractory material. This material is moldable and air-setting and may be a high alumina super duty clay, chrome ore, chrome magnesite or kaolin, for examples. The material is molded over the side faces and most of the edges of the metal body to form a sheathing, one to two or more inches in thickness.

In the construction of the sheathing the metal body l1, or core of the tube support, is provided with a reinforcing structure formed of networks of strands 24, preferably of wire. These are trained over anchoring elements borne by the body I1. Some of the anchoring elements are spaced over the opposite side faces of the body and others are spaced along edges of the body. As shown in Fig. 4, those on the faces of the body are in the form of hooks 25 of wire having shanks which are bent inward and welded as at 26, to the body. Fig. shows a pair of the anchoring elements borne by the upper edge of the body. There, a wire saddle 2l straddles the edge, and depending hooks 28 have a shank portion resting on the saddle. A pair of these hooks may be formed of a single strand of wire, and the hooks and saddle are welded together. Horizontal strands 30 of wire extend parallel to and spaced from each face of the body and are supported by the hooks 23 in a, position between the holes |8 and the recesses I3. Fig. 6 shows one of a number of pairs of anchoring elements spaced along the lower edge of the body. Each pair of elements may be formed of a single strand 29 of wire bent upwardly into an approximate pended from the upper anchoring elements and from the strand 3|). The various anchoring elements are formed and arranged to hold the reinforcing strands spaced substantially from the body Before molding the sheathing over the body the face and edge surfaces of the latter which are to be shielded by the sheathing are covered with a layer 32 of material which may, for eX- amples, be pasteboard, oil, grease or paint. Then, the ceramic material, in a plastic state, is molded over the body Il and the reinforcing structure so that the latter is intermediate the thickness of the material and so that all surfaces of the body are covered except bottom surfaces 33 of the holes I8 and of the notches I9, which receive the tubes, and the upper end portions of the tongues 20. The ceramic material is so molded as to form holes |8a which are smaller than the holes I8 and tangent to the lower side thereof and larger than the tubes 4.

A ceramic sheathing 34 encases the upper end portion of each tongue 20 and the suspension member 22 attached thereto. This sheathing may be integral with the sheathing 23 which encases the body of the tube support or it may be separately formed of the same ceramic material. For reinforcing the material a strand 35 of wire is helically Wound around the tongue and the suspension member 22. The ceramic material is molded over and around the reinforcement and covers the tongue and the suspension member from the tube support to the roof structure l0, the reinforcement being at an intermediate position in the thickness of the sheathing. Preferably the surfaces of the tongue, the suspension member and the joint therebetween which are covered by the sheathing 34 are also preferably covered with a layer of material such as oil, grease, paint or pasteboard, for examples, before the ceramic material is molded thereover.

The layer 32 of material between the body of the tube support and the sheathing 23 prevents bonding of the ceramic material of the sheathing to the surfaces covered thereby. -In service, said layer and the wood strip 3| will burn away and leave clearance between the metal body and the ceramic sheathing and enable them to expand and contract independently and thereby prevent cracking of the ceramic material under temperature changes. Similarly, the layer of material between the ceramic sheathing 34 and the tongues 23 and the suspension members 22 prevents bonding of the sheathing to the surfaces covered thereby and enables the ceramic sheathing and the metal parts to expand and contract independently and prevent cracking vof the sheathing under temperature changes.

In Figs. 7, 8 and 9 the structures of the tube support and its suspension means are similar to these just described except for. modificationv of the reinforcing means for the ceramic sheathing. In said gures, parts similar to the first de scribed form of the invention are designated by the same reference characters. In the modication, the reinforcing networks are anchored to the body of the tube support byelements 33. Each of these is formed of a short straight piece of wire welded at one end to the body l1, as at 31, and extending at right angles thereto and having its outer end portion bent at an angle to the body of the element. The elements 33 are suitably distributed over the side faces and the edges of the body including the edges defining the .holes I8, and the wire strands 24 are trained thereover to form the networks for reinforcingthe ceramic sheathing.

In Fig. 1 the improved tube supports S are shown as employed for supporting the-roof tubes 4 and 5 for the reason that such tubes and their supports are disposed across the outlet of the combustion chamber in the path of escaping hot combustion gases and corrosives borne thereby. When ordinary unprotected metal tube supports are employed in such a position and when highly corrosive vanadium oxides such as pentoXide or trioxide are present in the combustion gases and the gases are above a certain temperature the supports corrode rapidly to such a degree vthat they soon break under the weight of the tubes and permit the tubes to sag. Ordinarily, the fluid within the tubes cools them suliciently to render them substantially immune tocorrosion by such oxides. The tube supports however, are quite vulnerable.

IThe present invention provides for effectual protection of the tube supports from attack by vanadium oxides or other corrosives in the combustion gases by providing for exclusion 0f the gases from contact with all surfaces of the tube supports. The only metal surfaces not covered by the ceramic sheathing are the small surfaces 33 at the lower side of the tube-receiving holes I8 and the notches I9. These surfaces are left bare in order that they may directly contact the tubes and provide for transmission of the tube load directly to the metal body of the tube support instead of to the ceramic sheathing which might fracture under the load. In service, said surfaces 33 are covered and protected by the tubes, which also cool the surfaces, so that the gas exclusion is complete.

In both forms of the invention the Wire reinforcing networks and their anchoring elements will be of a material to resist the high operating temperature. For examples, suitable materials are 18-8 or 25-20 chrome-nickel.

While two satisfactory forms of the invention are disclosed it will be understood that the present disclosure is merely illustrative and in nowise limiting and that the invention comprehends such modifications as will come Within the scope of the following claims.

We claim:

1. A tube support for a heater of a type having horizontally extending tubes for circulating a uid to be heated and in which said tubes are disposed within a heating chamber in a position in which they are subjected to contact with hot gaseous products of combustion, comprising a vertical metal plate having spaced recesses each formed to receive at least a substantial portion f the cross section of one of said tubes, a sheathing of molded refractory non-metallic material covering the faces and edges of said plate includ-A ing the major portion of the surfaces defining said recesses, a minor portion only of the surface defining each recess and located at the bottom of the recess to be covered by the tube, being bare, for under support of the tube by contact with the metal plate, and reinforcing structure comprising crossed strands of metal arranged to prevent cracking of the sheathing in any direction extending over the opposite faces of the plate and within the thickness of the sheathing and With the material of the sheathing molded therearound, the adjacent surfaces of the sheathing and the plate being free from bond therebetween, for independent expansion and contraction of the plate and the sheathing.

2. The tube support of claim 1 wherein at least one of said tube-receiving recesses is located entirely within the contour of said plate and is surrounded by the plate and said sheathing.

3. The tube support of claim 1 including metal extensions leading upward from said plate for supporting same by suspension, a sheathing of molded refractory non-metallic material encasing each of said extensions, and metal reinforcement structure within said sheathings and with the material of the latter molded thereto.

4. The tube support of claim 1 including bifurcated elements within said sheathing straddling edges of said plate and with their legs connected to said reinforcing structure to anchor same to the plate.

OTTO C. SCHAUBLE. EDWARD FRANCIS TIBBETTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,499,787 Schaefer July 1, 1924 1,500,815 Hinman July 8, 1924 1,679,345 Austin Aug. 7, 1928 1,940,805 Kerr et al. Dec. 26, 1933 2,105,819 Parsons Jan. 18, 1938 

